Abstract:
Technology challenges lie ahead for the fuel and the vehicles. Automakers are working to accommodate alternatives to gasoline, as they're preparing for the long-term possibility that this planet might run out of petroleum that is cost-effective to extract and refine.

Advancements in battery design and the new science of nanotechnology might enable feasible new choices for the future. Fast-charging advanced batteries could eliminate the need to use hydrogen as a passenger-car fuel, but so far, that type of battery has been as elusive as inexpensive fuel cells.